sys/netinet6/ah_input.c

   1 /*      $FreeBSD: src/sys/netinet6/ah_input.c,v 1.1.2.6 2002/04/28 05:40:26 suz Exp $   */
   2 /*      $KAME: ah_input.c,v 1.67 2002/01/07 11:39:56 kjc Exp $  */
   3
   4 /*
   5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * RFC1826/2402 authentication header.
  35  */
  36
  37 #include "opt_inet.h"
  38 #include "opt_inet6.h"
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/malloc.h>
  43 #include <sys/mbuf.h>
  44 #include <sys/domain.h>
  45 #include <sys/protosw.h>
  46 #include <sys/socket.h>
  47 #include <sys/errno.h>
  48 #include <sys/time.h>
  49 #include <sys/syslog.h>
  50
  51 #include <net/if.h>
  52 #include <net/route.h>
  53 #include <net/netisr.h>
  54 #include <machine/cpu.h>
  55
  56 #include <netinet/in.h>
  57 #include <netinet/in_systm.h>
  58 #include <netinet/in_var.h>
  59 #include <netinet/ip.h>
  60 #include <netinet/ip_var.h>
  61 #include <netinet/ip_ecn.h>
  62 #ifdef INET6
  63 #include <netinet6/ip6_ecn.h>
  64 #endif
  65
  66 #ifdef INET6
  67 #include <netinet/ip6.h>
  68 #include <netinet6/ip6_var.h>
  69 #include <netinet6/in6_pcb.h>
  70 #include <netinet/icmp6.h>
  71 #include <netinet6/ip6protosw.h>
  72 #endif
  73
  74 #include <netinet6/ipsec.h>
  75 #ifdef INET6
  76 #include <netinet6/ipsec6.h>
  77 #endif
  78 #include <netinet6/ah.h>
  79 #ifdef INET6
  80 #include <netinet6/ah6.h>
  81 #endif
  82 #include <netkey/key.h>
  83 #include <netkey/keydb.h>
  84 #ifdef IPSEC_DEBUG
  85 #include <netkey/key_debug.h>
  86 #else
  87 #define KEYDEBUG(lev,arg)
  88 #endif
  89
  90 #include <machine/stdarg.h>
  91
  92 #include <net/net_osdep.h>
  93
  94 #define IPLEN_FLIPPED
  95
  96 #ifdef INET
  97 #include <netinet/ipprotosw.h>
  98 extern struct ipprotosw inetsw[];
  99
 100 void
 101 #if __STDC__
 102 ah4_input(struct mbuf *m, ...)
 103 #else
 104 ah4_input(m, va_alist)
 105         struct mbuf *m;
 106         va_dcl
 107 #endif
 108 {
 109         struct ip *ip;
 110         struct ah *ah;
 111         u_int32_t spi;
 112         const struct ah_algorithm *algo;
 113         size_t siz;
 114         size_t siz1;
 115         u_char *cksum;
 116         struct secasvar *sav = NULL;
 117         u_int16_t nxt;
 118         size_t hlen;
 119         int s;
 120         int off, proto;
 121         va_list ap;
 122         size_t stripsiz = 0;
 123
 124         va_start(ap, m);
 125         off = va_arg(ap, int);
 126         proto = va_arg(ap, int);
 127         va_end(ap);
 128
 129 #ifndef PULLDOWN_TEST
 130         if (m->m_len < off + sizeof(struct newah)) {
 131                 m = m_pullup(m, off + sizeof(struct newah));
 132                 if (!m) {
 133                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 134                                 "dropping the packet for simplicity\n"));
 135                         ipsecstat.in_inval++;
 136                         goto fail;
 137                 }
 138         }
 139
 140         ip = mtod(m, struct ip *);
 141         ah = (struct ah *)(((caddr_t)ip) + off);
 142 #else
 143         ip = mtod(m, struct ip *);
 144         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 145         if (ah == NULL) {
 146                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 147                         "dropping the packet for simplicity\n"));
 148                 ipsecstat.in_inval++;
 149                 goto fail;
 150         }
 151 #endif
 152         nxt = ah->ah_nxt;
 153 #ifdef _IP_VHL
 154         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 155 #else
 156         hlen = ip->ip_hl << 2;
 157 #endif
 158
 159         /* find the sassoc. */
 160         spi = ah->ah_spi;
 161
 162         if ((sav = key_allocsa(AF_INET,
 163                               (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
 164                               IPPROTO_AH, spi)) == 0) {
 165                 ipseclog((LOG_WARNING,
 166                     "IPv4 AH input: no key association found for spi %u\n",
 167                     (u_int32_t)ntohl(spi)));
 168                 ipsecstat.in_nosa++;
 169                 goto fail;
 170         }
 171         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 172                 printf("DP ah4_input called to allocate SA:%p\n", sav));
 173         if (sav->state != SADB_SASTATE_MATURE
 174          && sav->state != SADB_SASTATE_DYING) {
 175                 ipseclog((LOG_DEBUG,
 176                     "IPv4 AH input: non-mature/dying SA found for spi %u\n",
 177                     (u_int32_t)ntohl(spi)));
 178                 ipsecstat.in_badspi++;
 179                 goto fail;
 180         }
 181
 182         algo = ah_algorithm_lookup(sav->alg_auth);
 183         if (!algo) {
 184                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 185                     "unsupported authentication algorithm for spi %u\n",
 186                     (u_int32_t)ntohl(spi)));
 187                 ipsecstat.in_badspi++;
 188                 goto fail;
 189         }
 190
 191         siz = (*algo->sumsiz)(sav);
 192         siz1 = ((siz + 3) & ~(4 - 1));
 193
 194         /*
 195          * sanity checks for header, 1.
 196          */
 197     {
 198         int sizoff;
 199
 200         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 201
 202         /*
 203          * Here, we do not do "siz1 == siz".  This is because the way
 204          * RFC240[34] section 2 is written.  They do not require truncation
 205          * to 96 bits.
 206          * For example, Microsoft IPsec stack attaches 160 bits of
 207          * authentication data for both hmac-md5 and hmac-sha1.  For hmac-sha1,
 208          * 32 bits of padding is attached.
 209          *
 210          * There are two downsides to this specification.
 211          * They have no real harm, however, they leave us fuzzy feeling.
 212          * - if we attach more than 96 bits of authentication data onto AH,
 213          *   we will never notice about possible modification by rogue
 214          *   intermediate nodes.
 215          *   Since extra bits in AH checksum is never used, this constitutes
 216          *   no real issue, however, it is wacky.
 217          * - even if the peer attaches big authentication data, we will never
 218          *   notice the difference, since longer authentication data will just
 219          *   work.
 220          *
 221          * We may need some clarification in the spec.
 222          */
 223         if (siz1 < siz) {
 224                 ipseclog((LOG_NOTICE, "sum length too short in IPv4 AH input "
 225                     "(%lu, should be at least %lu): %s\n",
 226                     (u_long)siz1, (u_long)siz,
 227                     ipsec4_logpacketstr(ip, spi)));
 228                 ipsecstat.in_inval++;
 229                 goto fail;
 230         }
 231         if ((ah->ah_len << 2) - sizoff != siz1) {
 232                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv4 AH input "
 233                     "(%d should be %lu): %s\n",
 234                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 235                     ipsec4_logpacketstr(ip, spi)));
 236                 ipsecstat.in_inval++;
 237                 goto fail;
 238         }
 239
 240 #ifndef PULLDOWN_TEST
 241         if (m->m_len < off + sizeof(struct ah) + sizoff + siz1) {
 242                 m = m_pullup(m, off + sizeof(struct ah) + sizoff + siz1);
 243                 if (!m) {
 244                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 245                         ipsecstat.in_inval++;
 246                         goto fail;
 247                 }
 248
 249                 ip = mtod(m, struct ip *);
 250                 ah = (struct ah *)(((caddr_t)ip) + off);
 251         }
 252 #else
 253         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 254                 sizeof(struct ah) + sizoff + siz1);
 255         if (ah == NULL) {
 256                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 257                 ipsecstat.in_inval++;
 258                 goto fail;
 259         }
 260 #endif
 261     }
 262
 263         /*
 264          * check for sequence number.
 265          */
 266         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 267                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 268                         ; /* okey */
 269                 else {
 270                         ipsecstat.in_ahreplay++;
 271                         ipseclog((LOG_WARNING,
 272                             "replay packet in IPv4 AH input: %s %s\n",
 273                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 274                         goto fail;
 275                 }
 276         }
 277
 278         /*
 279          * alright, it seems sane.  now we are going to check the
 280          * cryptographic checksum.
 281          */
 282         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 283         if (!cksum) {
 284                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 285                     "couldn't alloc temporary region for cksum\n"));
 286                 ipsecstat.in_inval++;
 287                 goto fail;
 288         }
 289
 290         /*
 291          * some of IP header fields are flipped to the host endian.
 292          * convert them back to network endian.  VERY stupid.
 293          */
 294         ip->ip_len = htons(ip->ip_len + hlen);
 295         ip->ip_off = htons(ip->ip_off);
 296         if (ah4_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 297                 free(cksum, M_TEMP);
 298                 ipsecstat.in_inval++;
 299                 goto fail;
 300         }
 301         ipsecstat.in_ahhist[sav->alg_auth]++;
 302         /*
 303          * flip them back.
 304          */
 305         ip->ip_len = ntohs(ip->ip_len) - hlen;
 306         ip->ip_off = ntohs(ip->ip_off);
 307
 308     {
 309         caddr_t sumpos = NULL;
 310
 311         if (sav->flags & SADB_X_EXT_OLD) {
 312                 /* RFC 1826 */
 313                 sumpos = (caddr_t)(ah + 1);
 314         } else {
 315                 /* RFC 2402 */
 316                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 317         }
 318
 319         if (bcmp(sumpos, cksum, siz) != 0) {
 320                 ipseclog((LOG_WARNING,
 321                     "checksum mismatch in IPv4 AH input: %s %s\n",
 322                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 323                 free(cksum, M_TEMP);
 324                 ipsecstat.in_ahauthfail++;
 325                 goto fail;
 326         }
 327     }
 328
 329         free(cksum, M_TEMP);
 330
 331         m->m_flags |= M_AUTHIPHDR;
 332         m->m_flags |= M_AUTHIPDGM;
 333
 334 #if 0
 335         /*
 336          * looks okey, but we need more sanity check.
 337          * XXX should elaborate.
 338          */
 339         if (ah->ah_nxt == IPPROTO_IPIP || ah->ah_nxt == IPPROTO_IP) {
 340                 struct ip *nip;
 341                 size_t sizoff;
 342
 343                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 344
 345                 if (m->m_len < off + sizeof(struct ah) + sizoff + siz1 + hlen) {
 346                         m = m_pullup(m, off + sizeof(struct ah)
 347                                         + sizoff + siz1 + hlen);
 348                         if (!m) {
 349                                 ipseclog((LOG_DEBUG,
 350                                     "IPv4 AH input: can't pullup\n"));
 351                                 ipsecstat.in_inval++;
 352                                 goto fail;
 353                         }
 354                 }
 355
 356                 nip = (struct ip *)((u_char *)(ah + 1) + sizoff + siz1);
 357                 if (nip->ip_src.s_addr != ip->ip_src.s_addr
 358                  || nip->ip_dst.s_addr != ip->ip_dst.s_addr) {
 359                         m->m_flags &= ~M_AUTHIPHDR;
 360                         m->m_flags &= ~M_AUTHIPDGM;
 361                 }
 362         }
 363 #ifdef INET6
 364         else if (ah->ah_nxt == IPPROTO_IPV6) {
 365                 m->m_flags &= ~M_AUTHIPHDR;
 366                 m->m_flags &= ~M_AUTHIPDGM;
 367         }
 368 #endif /* INET6 */
 369 #endif /* 0 */
 370
 371         if (m->m_flags & M_AUTHIPHDR
 372          && m->m_flags & M_AUTHIPDGM) {
 373 #if 0
 374                 ipseclog((LOG_DEBUG,
 375                     "IPv4 AH input: authentication succeess\n"));
 376 #endif
 377                 ipsecstat.in_ahauthsucc++;
 378         } else {
 379                 ipseclog((LOG_WARNING,
 380                     "authentication failed in IPv4 AH input: %s %s\n",
 381                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 382                 ipsecstat.in_ahauthfail++;
 383                 goto fail;
 384         }
 385
 386         /*
 387          * update sequence number.
 388          */
 389         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 390                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 391                         ipsecstat.in_ahreplay++;
 392                         goto fail;
 393                 }
 394         }
 395
 396         /* was it transmitted over the IPsec tunnel SA? */
 397         if (sav->flags & SADB_X_EXT_OLD) {
 398                 /* RFC 1826 */
 399                 stripsiz = sizeof(struct ah) + siz1;
 400         } else {
 401                 /* RFC 2402 */
 402                 stripsiz = sizeof(struct newah) + siz1;
 403         }
 404         if (ipsec4_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 405                 /*
 406                  * strip off all the headers that precedes AH.
 407                  *      IP xx AH IP' payload -> IP' payload
 408                  *
 409                  * XXX more sanity checks
 410                  * XXX relationship with gif?
 411                  */
 412                 u_int8_t tos;
 413
 414                 tos = ip->ip_tos;
 415                 m_adj(m, off + stripsiz);
 416                 if (m->m_len < sizeof(*ip)) {
 417                         m = m_pullup(m, sizeof(*ip));
 418                         if (!m) {
 419                                 ipsecstat.in_inval++;
 420                                 goto fail;
 421                         }
 422                 }
 423                 ip = mtod(m, struct ip *);
 424                 /* ECN consideration. */
 425                 ip_ecn_egress(ip4_ipsec_ecn, &tos, &ip->ip_tos);
 426                 if (!key_checktunnelsanity(sav, AF_INET,
 427                             (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst)) {
 428                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 429                             "in IPv4 AH input: %s %s\n",
 430                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 431                         ipsecstat.in_inval++;
 432                         goto fail;
 433                 }
 434
 435 #if 1
 436                 /*
 437                  * Should the inner packet be considered authentic?
 438                  * My current answer is: NO.
 439                  *
 440                  * host1 -- gw1 === gw2 -- host2
 441                  *      In this case, gw2 can trust the authenticity of the
 442                  *      outer packet, but NOT inner.  Packet may be altered
 443                  *      between host1 and gw1.
 444                  *
 445                  * host1 -- gw1 === host2
 446                  *      This case falls into the same scenario as above.
 447                  *
 448                  * host1 === host2
 449                  *      This case is the only case when we may be able to leave
 450                  *      M_AUTHIPHDR and M_AUTHIPDGM set.
 451                  *      However, if host1 is wrongly configured, and allows
 452                  *      attacker to inject some packet with src=host1 and
 453                  *      dst=host2, you are in risk.
 454                  */
 455                 m->m_flags &= ~M_AUTHIPHDR;
 456                 m->m_flags &= ~M_AUTHIPDGM;
 457 #endif
 458
 459                 key_sa_recordxfer(sav, m);
 460                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 461                     ipsec_addhist(m, IPPROTO_IPV4, 0) != 0) {
 462                         ipsecstat.in_nomem++;
 463                         goto fail;
 464                 }
 465
 466                 s = splimp();
 467                 if (IF_QFULL(&ipintrq)) {
 468                         ipsecstat.in_inval++;
 469                         splx(s);
 470                         goto fail;
 471                 }
 472                 IF_ENQUEUE(&ipintrq, m);
 473                 m = NULL;
 474                 schednetisr(NETISR_IP); /* can be skipped but to make sure */
 475                 splx(s);
 476                 nxt = IPPROTO_DONE;
 477         } else {
 478                 /*
 479                  * strip off AH.
 480                  */
 481
 482                 ip = mtod(m, struct ip *);
 483 #ifndef PULLDOWN_TEST
 484                 /*
 485                  * We do deep-copy since KAME requires that
 486                  * the packet is placed in a single external mbuf.
 487                  */
 488                 ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), off);
 489                 m->m_data += stripsiz;
 490                 m->m_len -= stripsiz;
 491                 m->m_pkthdr.len -= stripsiz;
 492 #else
 493                 /*
 494                  * even in m_pulldown case, we need to strip off AH so that
 495                  * we can compute checksum for multiple AH correctly.
 496                  */
 497                 if (m->m_len >= stripsiz + off) {
 498                         ovbcopy((caddr_t)ip, ((caddr_t)ip) + stripsiz, off);
 499                         m->m_data += stripsiz;
 500                         m->m_len -= stripsiz;
 501                         m->m_pkthdr.len -= stripsiz;
 502                 } else {
 503                         /*
 504                          * this comes with no copy if the boundary is on
 505                          * cluster
 506                          */
 507                         struct mbuf *n;
 508
 509                         n = m_split(m, off, M_DONTWAIT);
 510                         if (n == NULL) {
 511                                 /* m is retained by m_split */
 512                                 goto fail;
 513                         }
 514                         m_adj(n, stripsiz);
 515                         m_cat(m, n);
 516                         /* m_cat does not update m_pkthdr.len */
 517                         m->m_pkthdr.len += n->m_pkthdr.len;
 518                 }
 519 #endif
 520
 521                 if (m->m_len < sizeof(*ip)) {
 522                         m = m_pullup(m, sizeof(*ip));
 523                         if (m == NULL) {
 524                                 ipsecstat.in_inval++;
 525                                 goto fail;
 526                         }
 527                 }
 528                 ip = mtod(m, struct ip *);
 529 #ifdef IPLEN_FLIPPED
 530                 ip->ip_len = ip->ip_len - stripsiz;
 531 #else
 532                 ip->ip_len = htons(ntohs(ip->ip_len) - stripsiz);
 533 #endif
 534                 ip->ip_p = nxt;
 535                 /* forget about IP hdr checksum, the check has already been passed */
 536
 537                 key_sa_recordxfer(sav, m);
 538                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0) {
 539                         ipsecstat.in_nomem++;
 540                         goto fail;
 541                 }
 542
 543                 if (nxt != IPPROTO_DONE) {
 544                         if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
 545                             ipsec4_in_reject(m, NULL)) {
 546                                 ipsecstat.in_polvio++;
 547                                 goto fail;
 548                         }
 549                         (*inetsw[ip_protox[nxt]].pr_input)(m, off, nxt);
 550                 } else
 551                         m_freem(m);
 552                 m = NULL;
 553         }
 554
 555         if (sav) {
 556                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 557                         printf("DP ah4_input call free SA:%p\n", sav));
 558                 key_freesav(sav);
 559         }
 560         ipsecstat.in_success++;
 561         return;
 562
 563 fail:
 564         if (sav) {
 565                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 566                         printf("DP ah4_input call free SA:%p\n", sav));
 567                 key_freesav(sav);
 568         }
 569         if (m)
 570                 m_freem(m);
 571         return;
 572 }
 573 #endif /* INET */
 574
 575 #ifdef INET6
 576 int
 577 ah6_input(mp, offp, proto)
 578         struct mbuf **mp;
 579         int *offp, proto;
 580 {
 581         struct mbuf *m = *mp;
 582         int off = *offp;
 583         struct ip6_hdr *ip6;
 584         struct ah *ah;
 585         u_int32_t spi;
 586         const struct ah_algorithm *algo;
 587         size_t siz;
 588         size_t siz1;
 589         u_char *cksum;
 590         struct secasvar *sav = NULL;
 591         u_int16_t nxt;
 592         int s;
 593         size_t stripsiz = 0;
 594
 595 #ifndef PULLDOWN_TEST
 596         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah), IPPROTO_DONE);
 597         ah = (struct ah *)(mtod(m, caddr_t) + off);
 598 #else
 599         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 600         if (ah == NULL) {
 601                 ipseclog((LOG_DEBUG, "IPv6 AH input: can't pullup\n"));
 602                 ipsec6stat.in_inval++;
 603                 return IPPROTO_DONE;
 604         }
 605 #endif
 606         ip6 = mtod(m, struct ip6_hdr *);
 607         nxt = ah->ah_nxt;
 608
 609         /* find the sassoc. */
 610         spi = ah->ah_spi;
 611
 612         if (ntohs(ip6->ip6_plen) == 0) {
 613                 ipseclog((LOG_ERR, "IPv6 AH input: "
 614                     "AH with IPv6 jumbogram is not supported.\n"));
 615                 ipsec6stat.in_inval++;
 616                 goto fail;
 617         }
 618
 619         if ((sav = key_allocsa(AF_INET6,
 620                               (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
 621                               IPPROTO_AH, spi)) == 0) {
 622                 ipseclog((LOG_WARNING,
 623                     "IPv6 AH input: no key association found for spi %u\n",
 624                     (u_int32_t)ntohl(spi)));
 625                 ipsec6stat.in_nosa++;
 626                 goto fail;
 627         }
 628         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 629                 printf("DP ah6_input called to allocate SA:%p\n", sav));
 630         if (sav->state != SADB_SASTATE_MATURE
 631          && sav->state != SADB_SASTATE_DYING) {
 632                 ipseclog((LOG_DEBUG,
 633                     "IPv6 AH input: non-mature/dying SA found for spi %u; ",
 634                     (u_int32_t)ntohl(spi)));
 635                 ipsec6stat.in_badspi++;
 636                 goto fail;
 637         }
 638
 639         algo = ah_algorithm_lookup(sav->alg_auth);
 640         if (!algo) {
 641                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 642                     "unsupported authentication algorithm for spi %u\n",
 643                     (u_int32_t)ntohl(spi)));
 644                 ipsec6stat.in_badspi++;
 645                 goto fail;
 646         }
 647
 648         siz = (*algo->sumsiz)(sav);
 649         siz1 = ((siz + 3) & ~(4 - 1));
 650
 651         /*
 652          * sanity checks for header, 1.
 653          */
 654     {
 655         int sizoff;
 656
 657         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 658
 659         /*
 660          * Here, we do not do "siz1 == siz".  See ah4_input() for complete
 661          * description.
 662          */
 663         if (siz1 < siz) {
 664                 ipseclog((LOG_NOTICE, "sum length too short in IPv6 AH input "
 665                     "(%lu, should be at least %lu): %s\n",
 666                     (u_long)siz1, (u_long)siz,
 667                     ipsec6_logpacketstr(ip6, spi)));
 668                 ipsec6stat.in_inval++;
 669                 goto fail;
 670         }
 671         if ((ah->ah_len << 2) - sizoff != siz1) {
 672                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv6 AH input "
 673                     "(%d should be %lu): %s\n",
 674                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 675                     ipsec6_logpacketstr(ip6, spi)));
 676                 ipsec6stat.in_inval++;
 677                 goto fail;
 678         }
 679 #ifndef PULLDOWN_TEST
 680         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1, IPPROTO_DONE);
 681 #else
 682         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 683                 sizeof(struct ah) + sizoff + siz1);
 684         if (ah == NULL) {
 685                 ipseclog((LOG_NOTICE, "couldn't pullup gather IPv6 AH checksum part"));
 686                 ipsec6stat.in_inval++;
 687                 m = NULL;
 688                 goto fail;
 689         }
 690 #endif
 691     }
 692
 693         /*
 694          * check for sequence number.
 695          */
 696         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 697                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 698                         ; /* okey */
 699                 else {
 700                         ipsec6stat.in_ahreplay++;
 701                         ipseclog((LOG_WARNING,
 702                             "replay packet in IPv6 AH input: %s %s\n",
 703                             ipsec6_logpacketstr(ip6, spi),
 704                             ipsec_logsastr(sav)));
 705                         goto fail;
 706                 }
 707         }
 708
 709         /*
 710          * alright, it seems sane.  now we are going to check the
 711          * cryptographic checksum.
 712          */
 713         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 714         if (!cksum) {
 715                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 716                     "couldn't alloc temporary region for cksum\n"));
 717                 ipsec6stat.in_inval++;
 718                 goto fail;
 719         }
 720
 721         if (ah6_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 722                 free(cksum, M_TEMP);
 723                 ipsec6stat.in_inval++;
 724                 goto fail;
 725         }
 726         ipsec6stat.in_ahhist[sav->alg_auth]++;
 727
 728     {
 729         caddr_t sumpos = NULL;
 730
 731         if (sav->flags & SADB_X_EXT_OLD) {
 732                 /* RFC 1826 */
 733                 sumpos = (caddr_t)(ah + 1);
 734         } else {
 735                 /* RFC 2402 */
 736                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 737         }
 738
 739         if (bcmp(sumpos, cksum, siz) != 0) {
 740                 ipseclog((LOG_WARNING,
 741                     "checksum mismatch in IPv6 AH input: %s %s\n",
 742                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 743                 free(cksum, M_TEMP);
 744                 ipsec6stat.in_ahauthfail++;
 745                 goto fail;
 746         }
 747     }
 748
 749         free(cksum, M_TEMP);
 750
 751         m->m_flags |= M_AUTHIPHDR;
 752         m->m_flags |= M_AUTHIPDGM;
 753
 754 #if 0
 755         /*
 756          * looks okey, but we need more sanity check.
 757          * XXX should elaborate.
 758          */
 759         if (ah->ah_nxt == IPPROTO_IPV6) {
 760                 struct ip6_hdr *nip6;
 761                 size_t sizoff;
 762
 763                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 764
 765                 IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1
 766                                 + sizeof(struct ip6_hdr), IPPROTO_DONE);
 767
 768                 nip6 = (struct ip6_hdr *)((u_char *)(ah + 1) + sizoff + siz1);
 769                 if (!IN6_ARE_ADDR_EQUAL(&nip6->ip6_src, &ip6->ip6_src)
 770                  || !IN6_ARE_ADDR_EQUAL(&nip6->ip6_dst, &ip6->ip6_dst)) {
 771                         m->m_flags &= ~M_AUTHIPHDR;
 772                         m->m_flags &= ~M_AUTHIPDGM;
 773                 }
 774         } else if (ah->ah_nxt == IPPROTO_IPIP) {
 775                 m->m_flags &= ~M_AUTHIPHDR;
 776                 m->m_flags &= ~M_AUTHIPDGM;
 777         } else if (ah->ah_nxt == IPPROTO_IP) {
 778                 m->m_flags &= ~M_AUTHIPHDR;
 779                 m->m_flags &= ~M_AUTHIPDGM;
 780         }
 781 #endif
 782
 783         if (m->m_flags & M_AUTHIPHDR
 784          && m->m_flags & M_AUTHIPDGM) {
 785 #if 0
 786                 ipseclog((LOG_DEBUG,
 787                     "IPv6 AH input: authentication succeess\n"));
 788 #endif
 789                 ipsec6stat.in_ahauthsucc++;
 790         } else {
 791                 ipseclog((LOG_WARNING,
 792                     "authentication failed in IPv6 AH input: %s %s\n",
 793                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 794                 ipsec6stat.in_ahauthfail++;
 795                 goto fail;
 796         }
 797
 798         /*
 799          * update sequence number.
 800          */
 801         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 802                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 803                         ipsec6stat.in_ahreplay++;
 804                         goto fail;
 805                 }
 806         }
 807
 808         /* was it transmitted over the IPsec tunnel SA? */
 809         if (sav->flags & SADB_X_EXT_OLD) {
 810                 /* RFC 1826 */
 811                 stripsiz = sizeof(struct ah) + siz1;
 812         } else {
 813                 /* RFC 2402 */
 814                 stripsiz = sizeof(struct newah) + siz1;
 815         }
 816         if (ipsec6_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 817                 /*
 818                  * strip off all the headers that precedes AH.
 819                  *      IP6 xx AH IP6' payload -> IP6' payload
 820                  *
 821                  * XXX more sanity checks
 822                  * XXX relationship with gif?
 823                  */
 824                 u_int32_t flowinfo;     /* net endian */
 825
 826                 flowinfo = ip6->ip6_flow;
 827                 m_adj(m, off + stripsiz);
 828                 if (m->m_len < sizeof(*ip6)) {
 829                         /*
 830                          * m_pullup is prohibited in KAME IPv6 input processing
 831                          * but there's no other way!
 832                          */
 833                         m = m_pullup(m, sizeof(*ip6));
 834                         if (!m) {
 835                                 ipsec6stat.in_inval++;
 836                                 goto fail;
 837                         }
 838                 }
 839                 ip6 = mtod(m, struct ip6_hdr *);
 840                 /* ECN consideration. */
 841                 ip6_ecn_egress(ip6_ipsec_ecn, &flowinfo, &ip6->ip6_flow);
 842                 if (!key_checktunnelsanity(sav, AF_INET6,
 843                             (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst)) {
 844                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 845                             "in IPv6 AH input: %s %s\n",
 846                             ipsec6_logpacketstr(ip6, spi),
 847                             ipsec_logsastr(sav)));
 848                         ipsec6stat.in_inval++;
 849                         goto fail;
 850                 }
 851
 852 #if 1
 853                 /*
 854                  * should the inner packet be considered authentic?
 855                  * see comment in ah4_input().
 856                  */
 857                 m->m_flags &= ~M_AUTHIPHDR;
 858                 m->m_flags &= ~M_AUTHIPDGM;
 859 #endif
 860
 861                 key_sa_recordxfer(sav, m);
 862                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 863                     ipsec_addhist(m, IPPROTO_IPV6, 0) != 0) {
 864                         ipsec6stat.in_nomem++;
 865                         goto fail;
 866                 }
 867
 868                 s = splimp();
 869                 if (IF_QFULL(&ip6intrq)) {
 870                         ipsec6stat.in_inval++;
 871                         splx(s);
 872                         goto fail;
 873                 }
 874                 IF_ENQUEUE(&ip6intrq, m);
 875                 m = NULL;
 876                 schednetisr(NETISR_IPV6); /* can be skipped but to make sure */
 877                 splx(s);
 878                 nxt = IPPROTO_DONE;
 879         } else {
 880                 /*
 881                  * strip off AH.
 882                  */
 883                 char *prvnxtp;
 884
 885                 /*
 886                  * Copy the value of the next header field of AH to the
 887                  * next header field of the previous header.
 888                  * This is necessary because AH will be stripped off below.
 889                  */
 890                 prvnxtp = ip6_get_prevhdr(m, off); /* XXX */
 891                 *prvnxtp = nxt;
 892
 893                 ip6 = mtod(m, struct ip6_hdr *);
 894 #ifndef PULLDOWN_TEST
 895                 /*
 896                  * We do deep-copy since KAME requires that
 897                  * the packet is placed in a single mbuf.
 898                  */
 899                 ovbcopy((caddr_t)ip6, ((caddr_t)ip6) + stripsiz, off);
 900                 m->m_data += stripsiz;
 901                 m->m_len -= stripsiz;
 902                 m->m_pkthdr.len -= stripsiz;
 903 #else
 904                 /*
 905                  * even in m_pulldown case, we need to strip off AH so that
 906                  * we can compute checksum for multiple AH correctly.
 907                  */
 908                 if (m->m_len >= stripsiz + off) {
 909                         ovbcopy((caddr_t)ip6, ((caddr_t)ip6) + stripsiz, off);
 910                         m->m_data += stripsiz;
 911                         m->m_len -= stripsiz;
 912                         m->m_pkthdr.len -= stripsiz;
 913                 } else {
 914                         /*
 915                          * this comes with no copy if the boundary is on
 916                          * cluster
 917                          */
 918                         struct mbuf *n;
 919
 920                         n = m_split(m, off, M_DONTWAIT);
 921                         if (n == NULL) {
 922                                 /* m is retained by m_split */
 923                                 goto fail;
 924                         }
 925                         m_adj(n, stripsiz);
 926                         m_cat(m, n);
 927                         /* m_cat does not update m_pkthdr.len */
 928                         m->m_pkthdr.len += n->m_pkthdr.len;
 929                 }
 930 #endif
 931                 ip6 = mtod(m, struct ip6_hdr *);
 932                 /* XXX jumbogram */
 933                 ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - stripsiz);
 934
 935                 key_sa_recordxfer(sav, m);
 936                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0) {
 937                         ipsec6stat.in_nomem++;
 938                         goto fail;
 939                 }
 940         }
 941
 942         *offp = off;
 943         *mp = m;
 944
 945         if (sav) {
 946                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 947                         printf("DP ah6_input call free SA:%p\n", sav));
 948                 key_freesav(sav);
 949         }
 950         ipsec6stat.in_success++;
 951         return nxt;
 952
 953 fail:
 954         if (sav) {
 955                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 956                         printf("DP ah6_input call free SA:%p\n", sav));
 957                 key_freesav(sav);
 958         }
 959         if (m)
 960                 m_freem(m);
 961         return IPPROTO_DONE;
 962 }
 963
 964 void
 965 ah6_ctlinput(cmd, sa, d)
 966         int cmd;
 967         struct sockaddr *sa;
 968         void *d;
 969 {
 970         const struct newah *ahp;
 971         struct newah ah;
 972         struct secasvar *sav;
 973         struct ip6_hdr *ip6;
 974         struct mbuf *m;
 975         struct ip6ctlparam *ip6cp = NULL;
 976         int off;
 977         struct sockaddr_in6 *sa6_src, *sa6_dst;
 978
 979         if (sa->sa_family != AF_INET6 ||
 980             sa->sa_len != sizeof(struct sockaddr_in6))
 981                 return;
 982         if ((unsigned)cmd >= PRC_NCMDS)
 983                 return;
 984
 985         /* if the parameter is from icmp6, decode it. */
 986         if (d != NULL) {
 987                 ip6cp = (struct ip6ctlparam *)d;
 988                 m = ip6cp->ip6c_m;
 989                 ip6 = ip6cp->ip6c_ip6;
 990                 off = ip6cp->ip6c_off;
 991         } else {
 992                 m = NULL;
 993                 ip6 = NULL;
 994         }
 995
 996         if (ip6) {
 997                 /*
 998                  * XXX: We assume that when ip6 is non NULL,
 999                  * M and OFF are valid.
1000                  */
1001
1002                 /* check if we can safely examine src and dst ports */
1003                 if (m->m_pkthdr.len < off + sizeof(ah))
1004                         return;
1005
1006                 if (m->m_len < off + sizeof(ah)) {
1007                         /*
1008                          * this should be rare case,
1009                          * so we compromise on this copy...
1010                          */
1011                         m_copydata(m, off, sizeof(ah), (caddr_t)&ah);
1012                         ahp = &ah;
1013                 } else
1014                         ahp = (struct newah *)(mtod(m, caddr_t) + off);
1015
1016                 if (cmd == PRC_MSGSIZE) {
1017                         int valid = 0;
1018
1019                         /*
1020                          * Check to see if we have a valid SA corresponding to
1021                          * the address in the ICMP message payload.
1022                          */
1023                         sa6_src = ip6cp->ip6c_src;
1024                         sa6_dst = (struct sockaddr_in6 *)sa;
1025                         sav = key_allocsa(AF_INET6,
1026                                           (caddr_t)&sa6_src->sin6_addr,
1027                                           (caddr_t)&sa6_dst->sin6_addr,
1028                                           IPPROTO_AH, ahp->ah_spi);
1029                         if (sav) {
1030                                 if (sav->state == SADB_SASTATE_MATURE ||
1031                                     sav->state == SADB_SASTATE_DYING)
1032                                         valid++;
1033                                 key_freesav(sav);
1034                         }
1035
1036                         /* XXX Further validation? */
1037
1038                         /*
1039                          * Depending on the value of "valid" and routing table
1040                          * size (mtudisc_{hi,lo}wat), we will:
1041                          * - recalcurate the new MTU and create the
1042                          *   corresponding routing entry, or
1043                          * - ignore the MTU change notification.
1044                          */
1045                         icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
1046                 }
1047
1048                 /* we normally notify single pcb here */
1049         } else {
1050                 /* we normally notify any pcb here */
1051         }
1052 }
1053 #endif /* INET6 */